Separation of columbium and tantalum



Dec. 5, 1961 J. O. GIBSON SEPARATION OF COLUMBIUM AND TANTALUM Filed Jan. 10, 1958 -2OO MESH ORE l CARBON -c1. HEAT 500C VOLATILE I Cb GL5 To cl.

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James 0. Gibson AIIQB IS United rates Patent 3,011,866 SEPARATION OF COLUMBIUM AND TANTALUM James 0. Gibson, LittletomCoio. (58 Whitman Drive, New Providence, NJ.) Filed Jan. 19, 1958, Ser. No. 708,307 7 Claims. (Cl. 23-47) This invention relates to a commercial process for the separation of columbian, otherwise known as niobium, and tantalum from ores containing the elements.

Columbium, or niobium, is almost always found associated with tantalum in ores, and in the United States and the Western Hemisphere the metals have always been found associated together in relatively low grade deposits. As the uses of columbium and tantalum have expanded, the low grade ores become a commercial source of the metals. Chemically columbium and tantalum are very similar, making their separation very difiicult. The known commercial processes for the separation of the two metals, which also includes the separation of the metals from a large number of other metals associated with them in ore which includes tungsten, molybdenum, iron, zircon, titanium, sodium potassium, calcium, etc., includes a fractional crystallization and a liquid-liquid extraction process. In each of these two known processes, however, the ore concentrates containing the metals are fused with sodium hydroxide, and the resultant products are leached with water and then with acid. The solutions of the metals are then subjected to the separation processes.

According to the present invention 1 provide a novel process for the separation of columbium from tantalum and for the separation of the two metals from other metals associated with them in an ore or an ore concentrate. The process includes an initial separation of columbiurn and tantalum and some of the other metals in a concentrate containing columbium, tantalum, and other metals, by heating oxides of the metals in the presence of carbon and chlorine to produce a volatile and a non-volatile fraction. The volatile fraction includes a major portion of the metals which are separated by condensation to produce a fraction containing a major portion of the tantalum and columbium. The columbium and tantalum values which are chlorides, resulting from the condensation are heated in the presence of carbon monoxide to provide separation of the columbium from the tantalum. One method is to heat the mixture in the presence of carbon While carbon dioxide gas is passing over the heated mixture. The carbon dioxide reacts with carbon to produce carbon monoxide. The carbon monoxide reacts with the metal chlorides to produce a volatile columbium and a non-volatile tantalum fraction. By hydrating separately the two fractions substantially pure columoium may be obtained from the volatile fraction while substantially pure tantalum oxide may be recovered from the non-volatile fraction.

Included among the objects and advantages of the present invention is to provide a simplified and highly efiicient method for the separation of columbium and tantalum from a concentrate of the natural ores of the same, and to separate the columbiurn and tantalum from metals which are associated with them in the ore. The invention, also, includes an economical and highly eflicient volatilization and distillation of compounds of columbium and tantalum and other metals associated with them in the ores, and thereby provide an effective separation of the metals. The process of the invention provides a nonaqueous method of separating columoium and tantalum.

These and other objects and advantages of the present invention may be readily ascertained by referring to the following description and appended illustrations in which:

FIG. 1 is a schematic flow sheet illustrating'process of the invention for separating columbium and tantalum from a concentrate of their ores, and

FIG. 2 is a cross sectional view'of a simplified batch process for carrying out the method of the invention, and includes a simplified flow sheet of the method for recovering and separating columbium and tantalum.

Example I In carrying out the process of the invention an ore concentrate containing columbiurn and tantalum ground to about 200 mesh is mixed with carbon. The mixture of concentrate and carbon was heated to about 500 C. and during the heating chlorine gas was passed through the mixture. A simplified batch process is illustrated in FIG. 2 where a mixture of five grams of columbium pentoxide and five grams of tantalum pentoxide are mixed with 1.1 grams of carbon and placed in a four foot length of one inch diameter Pyrex tubing 10. The mixture of the ore and carbon is placed between glass wool plugs 11, and a stopper 12 containing two inlets is placed in the end of the tube adjacent the ore-carbon mixture. The ore and carbon mixture is heated to 500 C. by a burner, and chlorine gas is introduced into the mixture through inlet 14 during the heating. This treatment converts the columbium and tantalum from the pentoxide form to the pentachloride form. The materials are sublimed and pass through the plug and condense at about positions 15 in the tube. When the conversion of the pentoxides to the pentachlorides is complete, the chlorine gas was ceased and carbon dioxide was introduced through inlet 16. The material sublimes in the presence of carbon monoxide (C-|-CO +heat=-2CO) then condenses along the tube. The heat is applied at 11. The material remaining at position 15 (the material which did not sublime) is dissolved in Water, and after filtering, the undissolved residue (by analysis) contains 89 plus percent of tantalum pentoxide and less than about 5% of columbium oxide. The material that sublimes is condensed on the cool part of the tube 17 near the outer end thereof. This condensed material is dissolved in water to hydrolyze the same. The aqueous mixture is filtered-to remove the soluble impurities, and the residue by assaying was shown to contain plus percent of columbium oxide and less than about 23% tantalum oxide. As illustrated in the partial fiow sheet, the non-soluble material from portion 15 of the tube after being hydrolyzed and filtered produced a material containing water (tantalic acid H Ta O which after being ignited was recovered as tantalum pentoxide. The same is true with the columbium which is recovered as a material having X waters of hydration (columbic acidH Cb O and on igniting the same is reduced to columbium pentoxide.

Example II A flotation concentrate (the mineral pyrochlore) from the Oka deposit in Quebec Province or" Canada was treated in a manner similar to that described in the figure for Example I. The concentrate analysis is as follows:

Patented Dec. 5, 1961 3,011,866 3 4 X-ray analysis (Merlyne Salmon): Percent ties, while the insoluble columbium is recovered as the Ce 1.4 oxide. La 0.4 In commercial practice it may be found advantageous Y 0.03 after fractiona-ting the titanium chloride away from the Zr 0.4 5 columbium chloride, tantalum chloride, iron chloride, Sr 0.3 etc. to place the columbium chloride, tantalum chlo- U 0.14 ride, etc. in a separate reaction vesseladd or pressurize Th 0.09 in the stoichiometric amount of carbon monoxide (CO) Zn 0.02 and then distill the columbium chloride away from the Cb 10.0 non-volatile fraction, thereby making more efiicient use Ta 0.5 of chemicals (C0, C0 and getting quantitative sepa- Fe 14.0 ration of the columbium and tantalum. Mn 1.3 Also, carbon monoxide gas is the chemical of choice Nd 0.4 and is readily metered 'as a fairly pure gas, rather than Ti 3.0 carbon dioxide gas. On a small scale it is convenient to generate it in the reaction equipment by passing car- The concentrate Was chlorinated by heating a 200 h di id through h b mesh ground ple i h chlorine gas to a temperature In the hydrolysis of sublimed anhydrous chloride ma- Of about After the chlorination. Was Completed, terials as described in the above examples, water or dilute carbon dioxide was Passed through the mixture to acid may be used, particularly in the final washings, lime OE various fractions thereof. The sublimed mateto remove the last n'aggs of soluble chlorides, rial was recovered, hydrolyzed in Water and filte'fed- The While the invention has been illustrated by reference hydrated material from Sublimed Portion Was ignitto specific embodiments, there is no intent to limit the ed and on analysis Showed that it contained 96% Colllmscope of the invention to the precise details so set forth, bium PfintOXide, 3% tantalum PentOXide and 05% 0f exceptinsofar as defined in the following claims. zirconium oxide. (This illustrated that carbon dioxide 1 l i made no separation; Example III illustrates that carbon 1 Th process of separating l bi lu f monoxide wasrequiredto formanen-volafile compound) tantalum values and from their natural ores which includes other metals comprising treating an intimate mix- Example ture of such an ore and carbon with chlorine gas at Another sample of the Oka ore (with carbon in accordabout 500 condansing the and h l ance with Example I) was chlorinated and after the reaction products of the resultant volatile composit on, pletion of the chlorination, carbon dioxide was passed "t the t columbmm and montalum through the ore with the heating being applied to the Wlth carbon monqxlde gas akabout 509 recovelmg Mm we shoem- The 3:25322 a;than;straits?isstanza sublimed material was recovered by condensation. After hydrolysis, filtering, and igniting the residue therefrom posmon as a tantalum l as before, the oxides analyzed 96.5% columbium pentox- The process of Separating columbium 7 from ide While tantalum pen/[oxide was not detected by the tantalum values and from thelrnaturalores Whlch lncludes analysis, (degree of detection about 0005 to 001% 40 other metals comprising treating an intimate mixture of tantalum pentoxide) and zirconium oxide was analyzed such an orefmd Carbon chlonne gas at about 9 to be present at about 0.6% C., condenslng the columblum and tantalum reaction The flow sheet of FIGURE 1 illustrates the process, products from theresultant volatile material, treating the where a charge of minus 200 mesh ore of a concentrate: condensed columbium and tantalum port ons with carbon thereof is heated to about 0 with about 110% monoxide gas a t ahout 500 C., recovering the result-ant of the theoretical amount of carbon required for oxide g ";PQf hydrolyzlglg the 1 30 reduction. Chlorine gas is passed through the heated coYere Vt1t1e C9mPOSit10I1 P use 60 11m "1111 charge to chlorinate the columbium, tantalum and sevi t l a p z p ttg, 'ff t y gg the trestualltant nogeral other metals. At about 450-500 C. columbium V0316 COmPOSI 10B @1130 0 P a an um 0X1 6 pentachloride, tantalum pentachloride and other chlo- 35a p p rides sublime from the charge. By distillation the other The Process of p i g columblumifalufis from chlorides may be efiectively separated as at A, by known tantalum values andfrom thelrnatural ores which includes procedures. The residue from the distillation step 2 is i i Ifiletals pg g l t gOL P heated to about 500 C. in the presence of carbon monox- 0 6 an Ore all car on a a on con enslng ide, as at stage 3 Where the volatile columbium composithe columbium and tantalum reaction products of the tion sublimes. This material is condensed and is hydroresultant volatile product, treating the condensed, columlyzed in water and the soluble impurities are filtered bium and tantalum portions with carbon monoxide gas at from the insoluble columbium p nt XidB- Th HOB-V013: about 500 C., recovering the resultant volatfle compositil idue of the third step is hydrolyzed in water and tion thereof, hyd-rolyzing the resultant recovered volatile the Soluble impufities filtered Ofi leaving an insoluble 6O composition with dilute acid to produce an insoluble Product of tantalum Oxide- The y y 0f the F columbium oxide, and hydrolyzing the resultant nonlllm iu and tantalum chlorides Produces a fine, volatile composition to produce an insoluble tantalum cult to filter composition and a filter aid, such asSe- 0Xide Pawn, y be used in the filtfation1 Usmg Pm 4. The process of separating columbium values from as the Oka the l q residue remaining from tantalum values and from their natural ores which inthe first stage chlorination includes such chlorides as socludes other metals comprisino Chlorinating an intimate dium chloride chloricle potassium chloride mixture of such an ore and carbon at about 500 C., conthoriumtchtlonde. uramum chloride manganese i g densing the columbium and tantalum chloride reaction rare it chlondes The Vela/let matter es products of the resultant volatile product, treating the columbium pentachlorlde, tantalum pentachlorlde, fer- 1 d 1 b rous chloride, zinc chloride, titanium chloride, tin chlocondeltsed c0 um mm an tfmta um portions Wlth car on ride, etc. The distillation step 2 removes titanium chlomonqxlde gas a 500 t resultant ride silicon chloride, etc; The volatile material leaving volattle c mposition, hydrolyzlng the said resultant stage/3 includes the columbium, iron, aluminum, etc. olat e composltlon to remove soluble lmpurltles a The iron, aluminum etc. are removed as soluble impurirecover an insoluble columbium oxide, and hydrolyzlng the non-volatile composition thereof to remove soluble impurities and recover an insoluble tantalum oxide.

5. The process of separating columbiurn values from tantalum Values and from their natural ores which includes other metals comprising chlorinating an intimate mixture of such an ore with carbon at about 500 C. to produce a first volatile composition inclusive of columbiurn and tantalum reaction products, fractionating the resultant first volatile composition to separate columbium and tantalum compositions, heating the columbium and tantalum compositions With carbon monoxide gas to about 500 C. to produce a second volatile composition and a non-volatile composition, hydrolyzing the second volatile composition with dilute acid to remove soluble impurities and recover an insoluble columbium oxide, and hydrolyzing the nonvolatile composition with dilute acid to remove soluble impurities and to recover an insoluble oxide.

6. In the process of separating columbium from tantalum and from mixtures containing the same, the steps which comprise heating a said mixture and carbon monoxide with chlorine gas at about 500 C. to form volatile and non-volatile compositions, hydrolyzing the resultant volatile compositions to recover insoluble columbium oxide therefrom, and hydrolyzing the resultant nonvolatile compositions from the heating step to recover insoluble tantalum oxide therefrom.

7. In the process of separating columbium from tantalum and from mixtures containing the same the steps which comprise heating a crude mixture of columbium pentachloride and tantalum pentachloride along with other metallic chlorides as impurities in the intimate presence of carbon monoxide at about 500 C. to form volatile and non-volatile compositions, hydrolyzing the resultant volatile compositions to recover insoluble columbiurn oxide from soluble impurities, and hydrolyzing the resultant non-volatile composition from the heating step to recover insoluble tantalum oxide from soluble impurities.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES May et al. in Industrial and Engineering Chemistry, December 1954, pages 2495-2500.

Hampel: Rare Metals Handbook, pub-l. by Reinhold Publ. Corp., N.Y., 1954, page 396-.

Mellor: Comprehensive Treatise on Inorganic and Theoretical Chemistry, vol. 9, 1929, page 843. 

1. THE PROCESS OF SEPARATING COLUMBIUM VALUES FROM TANTALUM VALUES AND FROM THEIR NATURAL ORES WHICH INCLUDES OTHER METALS COMPRISING TREATING AN INTIMATE MIXTURE OF SUCH AN ORE AND CARBON WITH CHLORINE GAS AT ABOUT 500*C., CONDENSING THE COLUMBIUM AND TANTALIUM REACTION PRODUCTS OF THE RESULTANT VOLATILE COMPOSITION, TREATING THE CONDENSED COLUMBIUM AND TANTALUM PORTIONS WITH CARBON MONOXIDE GAS AT ABOUT 500*C., RECOVERING THE RESULTANT VOLATILE COMPOSITION THEREOF AS A COLUMBIUM PRODUCT, AND RECOVERING THE RESULTANT NON-VOLATILE COMPOSITION AS A TANTALUM PRODUCT. 